[AI] Implement sync recovery (#7111)

* [AI] Fix iOS/Safari sync recovery (fixes #7026): useOnVisible hook, re-fetch server version on visible, improved network-failure message

Made-with: Cursor

* Feedback: coderabbitai

* Refactor useOnVisible test: remove unnecessary resolve check and simplify callback definition

AGENTS.md

@@ -314,6 +314,7 @@ Always run `yarn typecheck` before committing.
 
 **React Patterns:**
 
+- The project uses **React Compiler** (`babel-plugin-react-compiler`) in the desktop-client. The compiler auto-memoizes component bodies, so you can omit manual `useCallback`, `useMemo`, and `React.memo` when adding or refactoring code; prefer inline callbacks and values unless a stable identity is required by a non-compiled dependency.
 - Don't use `React.FunctionComponent` or `React.FC` - type props directly
 - Don't use `React.*` patterns - use named imports instead
 - Use `<Link>` instead of `<a>` tags

packages/desktop-client/src/components/App.tsx

@@ -34,6 +34,7 @@ import {
 import { handleGlobalEvents } from '@desktop-client/global-events';
 import { useIsTestEnv } from '@desktop-client/hooks/useIsTestEnv';
 import { useMetadataPref } from '@desktop-client/hooks/useMetadataPref';
+import { useOnVisible } from '@desktop-client/hooks/useOnVisible';
 import { SpreadsheetProvider } from '@desktop-client/hooks/useSpreadsheet';
 import { setI18NextLanguage } from '@desktop-client/i18n';
 import { addNotification } from '@desktop-client/notifications/notificationsSlice';
@@ -179,6 +180,11 @@ export function App() {
   );
   const dispatch = useDispatch();
 
+  useOnVisible(async () => {
+    console.debug('triggering sync because of visibility change');
+    await dispatch(sync());
+  });
+
   useEffect(() => {
     function checkScrollbars() {
       if (hiddenScrollbars !== hasHiddenScrollbars()) {
@@ -186,25 +192,9 @@ export function App() {
       }
     }
 
-    let isSyncing = false;
-
-    async function onVisibilityChange() {
-      if (!isSyncing) {
-        console.debug('triggering sync because of visibility change');
-        isSyncing = true;
-        await dispatch(sync());
-        isSyncing = false;
-      }
-    }
-
     window.addEventListener('focus', checkScrollbars);
-    window.addEventListener('visibilitychange', onVisibilityChange);
-
-    return () => {
-      window.removeEventListener('focus', checkScrollbars);
-      window.removeEventListener('visibilitychange', onVisibilityChange);
-    };
-  }, [dispatch, hiddenScrollbars]);
+    return () => window.removeEventListener('focus', checkScrollbars);
+  }, [hiddenScrollbars]);
 
   const [theme] = useTheme();
 

packages/desktop-client/src/components/ServerContext.tsx

@@ -12,6 +12,7 @@ import { t } from 'i18next';
 import { send } from 'loot-core/platform/client/connection';
 import type { Handlers } from 'loot-core/types/handlers';
 
+import { useOnVisible } from '@desktop-client/hooks/useOnVisible';
 import { addNotification } from '@desktop-client/notifications/notificationsSlice';
 import { useDispatch } from '@desktop-client/redux';
 
@@ -110,6 +111,16 @@ export function ServerProvider({ children }: { children: ReactNode }) {
     void run();
   }, []);
 
+  useOnVisible(
+    async () => {
+      const version = await getServerVersion();
+      setVersion(version);
+    },
+    {
+      isEnabled: !!serverURL,
+    },
+  );
+
   const refreshLoginMethods = useCallback(async () => {
     if (serverURL) {
       const data: Awaited<ReturnType<Handlers['subscribe-get-login-methods']>> =

packages/desktop-client/src/components/manager/ConfigServer.tsx

@@ -313,7 +313,7 @@ export function ConfigServer() {
     switch (error) {
       case 'network-failure':
         return t(
-          'Server is not running at this URL. Make sure you have HTTPS set up properly.',
+          'Connection failed. If you use a self-signed certificate or were recently offline, try refreshing the page. Otherwise ensure you have HTTPS set up properly.',
         );
       default:
         return t(

packages/desktop-client/src/hooks/useOnVisible.test.ts

@@ -0,0 +1,108 @@
+import { renderHook } from '@testing-library/react';
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+
+import { useOnVisible } from './useOnVisible';
+
+function setVisibilityState(value: DocumentVisibilityState) {
+  Object.defineProperty(document, 'visibilityState', {
+    value,
+    configurable: true,
+    writable: true,
+  });
+}
+
+function dispatchVisibilityChange() {
+  document.dispatchEvent(new Event('visibilitychange'));
+}
+
+describe('useOnVisible', () => {
+  const originalVisibilityState = document.visibilityState;
+
+  beforeEach(() => {
+    setVisibilityState('visible');
+  });
+
+  afterEach(() => {
+    setVisibilityState(originalVisibilityState);
+    vi.clearAllMocks();
+  });
+
+  it('invokes callback when document becomes visible', () => {
+    const callback = vi.fn();
+    renderHook(() => useOnVisible(callback));
+
+    dispatchVisibilityChange();
+
+    expect(callback).toHaveBeenCalledTimes(1);
+  });
+
+  it('does not invoke callback when visibilityState is hidden', () => {
+    const callback = vi.fn();
+    renderHook(() => useOnVisible(callback));
+
+    setVisibilityState('hidden');
+    dispatchVisibilityChange();
+
+    expect(callback).not.toHaveBeenCalled();
+  });
+
+  it('does not attach listener when isEnabled is false', () => {
+    const callback = vi.fn();
+    renderHook(() => useOnVisible(callback, { isEnabled: false }));
+
+    dispatchVisibilityChange();
+
+    expect(callback).not.toHaveBeenCalled();
+  });
+
+  it('stops invoking callback after unmount', () => {
+    const callback = vi.fn();
+    const { unmount } = renderHook(() => useOnVisible(callback));
+
+    unmount();
+    dispatchVisibilityChange();
+
+    expect(callback).not.toHaveBeenCalled();
+  });
+
+  it('invokes callback on every visibilitychange when visibilityState is visible', async () => {
+    const callback = vi.fn();
+    renderHook(() => useOnVisible(callback));
+
+    dispatchVisibilityChange();
+    expect(callback).toHaveBeenCalledTimes(1);
+
+    await Promise.resolve();
+    dispatchVisibilityChange();
+    expect(callback).toHaveBeenCalledTimes(2);
+  });
+
+  it('does not invoke callback again until previous async callback completes', async () => {
+    let resolve: () => void;
+    const callback = vi.fn().mockImplementation(
+      () =>
+        new Promise<void>(r => {
+          resolve = r;
+        }),
+    );
+    renderHook(() => useOnVisible(callback));
+
+    dispatchVisibilityChange();
+    dispatchVisibilityChange();
+    expect(callback).toHaveBeenCalledTimes(1);
+
+    resolve();
+    await Promise.resolve();
+    dispatchVisibilityChange();
+    expect(callback).toHaveBeenCalledTimes(2);
+  });
+
+  it('invokes callback when isEnabled is true by default', () => {
+    const callback = vi.fn();
+    renderHook(() => useOnVisible(callback));
+
+    dispatchVisibilityChange();
+
+    expect(callback).toHaveBeenCalledTimes(1);
+  });
+});

packages/desktop-client/src/hooks/useOnVisible.ts

@@ -0,0 +1,47 @@
+import { useEffect, useEffectEvent, useRef } from 'react';
+
+type UseOnVisibleOptions = {
+  /** When false, the visibility listener is not attached. Default true. */
+  isEnabled?: boolean;
+};
+
+/**
+ * Runs the given callback when the document becomes visible (e.g. user
+ * switches back to the tab). Uses a guard so the callback is not invoked
+ * again until the previous invocation has finished (handles async callbacks).
+ */
+export function useOnVisible(
+  callback: () => void | Promise<void>,
+  options: UseOnVisibleOptions = {},
+) {
+  const { isEnabled = true } = options;
+  const inProgress = useRef(false);
+
+  const runCallback = useEffectEvent(async () => {
+    if (inProgress.current) {
+      return;
+    }
+    inProgress.current = true;
+    try {
+      await callback();
+    } finally {
+      inProgress.current = false;
+    }
+  });
+
+  useEffect(() => {
+    if (!isEnabled) {
+      return;
+    }
+    function onVisibilityChange() {
+      if (document.visibilityState !== 'visible') {
+        return;
+      }
+      void runCallback();
+    }
+
+    document.addEventListener('visibilitychange', onVisibilityChange);
+    return () =>
+      document.removeEventListener('visibilitychange', onVisibilityChange);
+  }, [isEnabled]);
+}

upcoming-release-notes/7111.md

@@ -0,0 +1,6 @@
+---
+category: Enhancements
+authors: [MatissJanis]
+---
+
+Reload server version when visibility to the page changes